Model tropical cyclone behaviour in experiments related to modification attempts

A numerical model of tropical cyclone development (Sundqvist, 1970α) has been used to study and compare the effects on the cyclone intensity by cloud seeding and spatial variations of sea surface temperature. The cloud seeding is simulated by taking into account heat released by freezing for temperatures below 0° C at selected radii of the convective area. The movement of a cyclone over a sea surface with a non-homogeneous temperature distribution is simulated in this axi-symmetric model by changing the sea temperature from one period of time to another inside a certain radius. The results indicate that the maximum winds of the symmetric model tropical cyclone rather have a tendency to intensify than to decrease when cloud seeding is employed. The results of the experiments simulating a fluctuating sea surface temperature show that even rather small scale (even smaller than the size of the convective region) variations significantly affect the intensity of a tropical cyclone.